Cancelling Account

Having spent over 30 minutes on 3 separate occasions having been put on hold, I just can't get through to anybody at PlusNet in order to cancel my account.I must say that standards have dropped. My broadband drops quite regularly now, my speeds are not what they used to be and the normally excellent customer service when phoning is now non-existent. Have Plusnet expanded too much?Is there another way to get my MAC code? Can I e-mail, or can Plusnet phone me?Argh!